add a value to an array from another array javascript code example

Example 1: insert into array js

// for me lol... pls don't delete!
// use splice to insert element
// arr.splice(index, numItemsToDelete, item); 
var list = ["hello", "world"]; 
list.splice( 1, 0, "bye"); 
//result
["hello", "bye", "world"]

Example 2: add array to array javascript

// SPREAD OPERATOR
 const list1 = ["pepe", "luis", "rua"];
 const list2 = ["rojo", "verde", "azul"];
 const newList = [...list1, ...list2];
 // ["pepe", "luis", "rua", "rojo", "verde", "azul"]